Display device

ABSTRACT

A display device is provided. The display device includes a display panel, a backlight unit, and a rear chassis. The display panel is configured to display an image. The backlight unit is provided on a rear surface of the display panel. The rear chassis includes a protruding region, a vibration plate, and at least one acoustic element. The protruding region is protruded in a rear direction. The at least one acoustic element is provided in the vibration plate and includes a pair of electrodes and a vibration material layer provided therebetween. The protruding region and the vibration plate are made of different materials.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation of co-pending U.S. patent applicationSer. No. 14/504,951 filed on Oct. 2, 2014, which claims priority under35 U.S.C. § 119 to Korean Patent Application No. 10-2013-0167500 filedon Dec. 30, 2013 in the Korean Intellectual Property Office, thedisclosures of which are incorporated by reference herein in theirentirety.

TECHNICAL FIELD

The present invention relates to a display device, and more particularlyto a display device which not only displays an image but also generatesa sound or vibration.

DISCUSSION OF THE RELATED ART

Display devices such as a liquid crystal display (LCD), a plasma displaypanel (PDP), an organic light emitting display (OLED), an electrowettingdisplay (EWD), an electrophoretic display (EPD), an embedded microcavitydisplay (EMD), and a nanocrystal display (NCD) have been developed.

However, most of the display devices may have only a function ofdisplaying an image. To provide functions of generating a sound,detecting a touch, and sensing a motion, elements such as a speaker, atouch sensor, and/or a motion sensor may be formed additionally to thedisplay devices and thus, a manufacturing cost for the display devicesmay be increased.

SUMMARY

An exemplary embodiment of the present invention provides a displaydevice. The display device includes a display panel, a backlight, and arear chassis. The display panel is configured to display an image. Thebacklight unit is disposed on a rear surface of the display panel. Therear chassis includes a first protruding region, a first vibrationplate, and at least one first acoustic element. The first protrudingregion is protruded in a rear direction. The at least one first acousticelement is disposed in the vibration plate. The at least one firstacoustic element includes a first electrode, a second electrode, and avibration material layer provided between the first and secondelectrodes. The first protruding region and the first vibration plateare made of different materials.

The first protruding region may include a metal, and the vibration plateincludes at least one of leather, artificial leather, a polyetherimide(PEI) film, or a material forming a speaker edge.

The protruding region may have a dual protruding structure including afirst sub protruding region and a second sub protruding region protrudedin the first sub protruding, and the first vibration plate is providedon the second sub protruding region.

The display device may further include a first fixing member configuredto connect a portion of the second sub protruding region to the firstvibration plate.

The rear chassis may further include a second protruding region, asecond vibration plate, and at least one second acoustic element. Thesecond protruding region is protruded in the rear direction. The secondprotruding region has a third sub protruding region and a fourth subprotruding region positioned protruded in the third sub protrudingregion. The second vibration plate is disposed in the fourth subprotruding region. The at least one second acoustic element is disposedin the second vibration plate. The second protruding region is spacedapart from the first protruding region.

The rear chassis may further include at least one opening configured todischarge a sound.

The rear chassis may further include a wiring connection member formedwith an acoustic signal wire which receives an acoustic signal from anamplifier. The wiring connection member may be formed at the firstprotruding region.

The at least one first acoustic element may be attached to a portion ofthe first vibration plate by an adhesive, and the adhesive includes anon-conductive epoxy.

The first electrode through which the acoustic element is attached tothe vibration plate may be extended to be connected to an electrode padthrough a side of the vibration material layer. The electrode pad may bedisposed on a top surface of the vibration material layer and may bespaced apart from the second electrode disposed on the top surface ofthe vibration material layer.

An electric field may be applied to the vibration material layer throughthe second electrode and the electrode pad.

The at least one first acoustic element may include three vibrationmaterial layers and four electrodes. The three vibration material layersmay be arranged in a three-layered structure, and the four electrodesmay be disposed at outermost surfaces of the vibration material layersand between the three vibration material layers.

Among the four electrodes, the electrode disposed at a lowermost surfaceof the vibration material layer may be extended to be connected to anelectrode pad through a side of the three vibration material layers. Theelectrode pad may be disposed on a uppermost surface of the threevibration material layers. The electrode pad may be spaced apart fromthe second electrode disposed at the uppermost surface of the threevibration material layers.

The four electrodes may be electrically connected to each other two bytwo. Adjacent electrodes among the four electrodes may not beelectrically connected to each other.

The display device may further include an amplifier and an acousticsignal wire. The amplifier may be configured to amplify an acousticsignal, and the acoustic signal wire may be configured to transfer theacoustic signal from the amplifier to the at least one first acousticelement.

The display panel may include a printed circuit board and a flexibleprinted circuit board. The substrate of the display panel may beconnected with the printed circuit board through the flexible printedcircuit board, and the amplifier may be formed on the printed circuitboard.

The vibration material layer of the at least one first acoustic elementmay be configured to generate vibration having a first frequency otherthan an audible frequency. A touch to the display device may be detectedby using a change of vibration in the first frequency.

A pressure to the display device may be sensed by using a voltage in thevibrating material layer generated when an electric field is not appliedto the vibrating material layer.

The display device may further include a microphone configured to sensea motion generated around the display device by using an acousticpressure of a sound wave generated according to the motion.

The display device may further include a battery configured to supply apower to the display device, and the battery may be charged by a voltagegenerated when the at least one first acoustic element vibrates.

An exemplary embodiment of the present invention provides a rear chassisin a display device. The rear chassis includes a vibration plate, aprotruding region, and at least one acoustic element. The protrudingregion has a first sub protruding region and a second protruding regionprotruded in the first sub protruding region. The at least one acousticelement is disposed in the vibration plate. The at least one acousticelement includes a first electrode, a second electrode, and a vibrationmaterial layer. The at least acoustic element is disposed in thevibration plate through the first electrode. The vibration materiallayer is disposed on the first electrode. The second electrode isdisposed on the vibration material layer. An electrode pad is spacedapart from the second electrode, is disposed on the vibration materiallayer, and is connected to the first electrode through a side of thevibration material layer.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present disclosure and many of theattendant aspects thereof will be readily obtained as the same becomesbetter understood by reference to the following detailed descriptionwhen considered in connection with the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of a display device in accordance withan exemplary embodiment of the present invention;

FIG. 2 is a rear view of a display device in accordance with anexemplary embodiment of the present invention;

FIGS. 3A to 3G, 4, and 5 illustrate a display device in accordance withvarious modifications of an exemplary embodiment of the presentinvention;

FIGS. 6 to 8 illustrate various structures of an acoustic element inaccordance with various modifications of an exemplary embodiment of thepresent invention;

FIG. 9 illustrates an amplifier in a display device in accordance withan exemplary embodiment of the present invention; and

FIGS. 10 to 14 illustrate a display device sensing a user's touch or auser's motion in accordance with an exemplary embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings. Thepresent invention may, however, be embodied in various forms withoutdeparting from the spirit or scope of the present invention and shouldnot be construed as being limited to the embodiments set forth herein.

In the drawings, the thickness of layers, films, panels, regions, etc.,may be exaggerated for clarity. Like reference numerals may designatelike elements throughout the specification.

Hereinafter, a display device in accordance with an exemplary embodimentof the present invention will be described in detail with reference toFIGS. 1 and 2.

FIG. 1 is a cross-sectional view of the display device according to theexemplary embodiment of the present invention, and FIG. 2 is a rear viewof the display device in accordance with the exemplary embodiment of thepresent invention.

Referring to FIG. 1, the display device includes a display panel 100 anda backlight unit provided on a back surface of the display panel 100.The backlight unit includes a light source 21, a light guide 22, anoptical sheet 23, a rear chassis 28, and an acoustic element 27. Therear chassis 28 includes first and second protruding regions 28-1 and28-2 and a vibration plate 29-1. The acoustic element 27 is providedinside the vibration plate 29-1. Herein, the rear chassis 28 may bereferred to as “a bottom chassis” or “a back chassis”, or various otherterms. For example, the rear chassis 28 might not be included in thebacklight unit.

In FIG. 1, the display panel 100 may be a light receiving type ofdisplay panel that receives light from a light source to display animage. Examples of the light receiving type display panel may include aliquid crystal panel, an electrophoretic display panel, and anelectrowetting display panel.

The display panel 100 includes a thin film transistor (TFT) substrateformed of a plurality of TFTs, and the TFT substrate is a transparentinsulating substrate formed with the thin film transistors in a matrixtype. In addition, a source terminal of each TFT is connected to a dataline, and a gate terminal of each TFT is connected to a gate line.Further, a drain terminal of each TFT may be connected to a pixelelectrode made of transparent indium tin oxide (ITO) as a conductivematerial. A polarizer may be attached to a top surface and/or a bottomsurface of the display panel 100. A detailed structure of the displaypanel 100 may be embodied in various forms according to a kind ofdisplay.

Although not shown, the display panel 100 shown in FIG. 1 may include aprinted circuit board (PCB) and a flexible printed circuit board (FPC)attached to the outside of the display panel 100

When the data line and the gate line of the display panel 100 areconnected to the FPC and receive electrical signals input from the FPC,the electrical signals are transferred to a source terminal and a gateterminal of the TFT. For example, the TFT is turned on or off accordingto a scanning signal applied to the gate terminal through the gate lineand thus an image signal applied to the source terminal through the dataline is transferred to or blocked from the drain terminal. The FPCreceives the image signal from the outside of the display panel to applyrespective driving signals to the data line and the gate line of thedisplay panel.

The FPC generates an image signal and a scanning signal for driving thedisplay device 100, and a plurality of timing signals for applying theimage signal and the scanning signal with appropriate timing, andapplies the image signal and the scanning signal to the gate line andthe data line of the display panel 100, respectively. In addition, theFPC according to the exemplary embodiment of the present invention mayinclude an amplifier, as illustrated in FIG. 10, that amplifies andtransfers an acoustic signal. The amplifier receives the acoustic signalfrom the outside, amplifies the received acoustic signal, and transfersthe acoustic signal to the acoustic element 27 through an acousticsignal wire.

The display panel 100 may further include a mold frame, and the moldframe serves to fix the display panel 100 and the backlight unit incooperation with the rear chassis 28. In addition, the display panel 100may further include a top chassis for preventing the display panel 100from deviating in a front direction of the display panel 100, inaccordance with an exemplary embodiment of the present invention.

The display panel 100 requires light to display an image, and thus thebacklight unit basically supplies light toward the display panel 100. Tothat end, the backlight unit includes the light source 21, the lightguide 22, and the optical sheet 23. As the light source 21, an LED or afluorescent lamp such as a cold cathode fluorescent lamp (CCFL) may beused. Light emitted from the light source 21 is transferred to thedisplay panel 100 through the light guide 22 and the optical sheet 23.The light guide 22 transfers the light supplied from the light source 21in a front direction DR1 of the display device, and a protrusion patternmay be formed to refract light in the front direction DR1. In FIG. 1, anedge type of backlight unit in which the light source 21 is provided ata side thereof is shown, however, the present invention is not limitedthereto. For example, a direct type of backlight unit in which the lightsource 21 is provided at a lower surface thereof may be employed inaccordance with an exemplary embodiment of the present invention. Inthis case, the light guide 22 might not be necessary. The optical sheet23 is disposed on a top surface of the light guide 22. For example, aplurality of optical sheets 23 may be formed. The plurality of opticalsheets 23 may include at least one of a diffuser sheet for diffusinglight, a prism sheet having a prism structure for focusing light, and aluminance improving film in which two layers having different refractiveindices are repeatedly formed. Although not shown in FIG. 1, areflective sheet may be provided on a bottom surface of the light guide22. The reflective sheet may reflect light refracted in a rear directionDR2 of the display device toward the front direction DR1.

The rear chassis 28 supports and protects the light source 21, theoptical sheet 23, and the light guide 22. The rear chassis 28 may belocated on a rear surface of the display panel 100 to accommodate andprotect the display panel 100. The rear chassis 28 may be coupled to atop chassis or a mold frame of the display panel 100 to protect thedisplay panel 100 in accordance with an exemplary embodiment of thepresent invention.

The rear chassis 28 may include a protruding region which protrudes inthe rear direction DR2. In FIG. 1, the rear chassis 28 has a dualprotruding structure including the first and second protruding regions28-1 and 28-2. The protruding degree and the width of the first andsecond protruding regions 28-1 and 28-2 are enlarged in FIG. 1, butactually, the protruding degree might not be easily recognized with thenaked eye. The first protruding region 28-1 has a structure in which therear chassis 28 is extended from the light guide 22 or the reflectivesheet and is protruded in the rear direction DR2. In FIG. 1, the firstprotruding region 28-1 has a circularly protruding structure, asillustrated in FIG. 2. The second protruding region 28-2 furtherprotrudes in the first protruding region 28-1. In FIG. 1, the secondprotruding region 28-2 has a circularly protruding structure similar tothe first protruding region 28-1, as illustrated in FIG. 2.

A vibration plate 29-1 is provided on a protruding bottom surface of thesecond protruding region 28-2

The vibration plate 29-1 is fixed by using the bottom surface of thesecond protruding region 28-2 and a fixing member 29, and is made of amaterial that is different from that of the second protruding region28-2. For example, the rear chassis 28, the first protruding region28-1, and the second protruding region 28-2 are made of substantiallythe same metallic material which forms the chassis 28, but the vibrationplate 29-1 and the fixing member 29 are made of a material that isdifferent from the metallic material. The vibration plate 29-1 may beformed of leather, artificial leather, a polyetherimide (PEI) film, or amaterial of a speaker edge (e.g., a part connecting a speaker body witha vibration unit). The fixing member 29 may be formed of a material thatis different from that of the vibration plate 29-1 or substantially thesame material as that of the vibration plate 29-1 such as leather,artificial leather, a PEI film, and a material of a speaker edge (e.g.,a part connecting a speaker body with a vibration unit).

The vibration plate 29-1 is made of a non-metallic material differentlyfrom the first and second protruding region 28-1 and 28-2 to reduce ametallic sound (e.g., high pitched sound frequency) and strengthen a lowpitched sound. The vibration plate 29-1 may serve as a woofer bystrengthening the low pitched sound. In addition, the first and secondprotruding regions 28-1 and 28-2 serve as a sound box. The size of thesound box may be increased by increasing the number of protrudingregions. In FIG. 1, two protruding regions 28-1 and 28-2 are used. If asufficient sound box is obtained by using one protruding region, oneprotruding region may be used. However, the present invention is notlimited thereto. For example, three or more protruding regions may beused.

Referring to FIG. 1, the acoustic element 27 is attached to the insideof the vibration plate 29-1 of the rear chassis 28 by an adhesive (notshown). The acoustic element 27 includes a pair of electrodes 27-2 and avibration material layer 27-1 disposed between the electrodes 27-2. Theadhesive may include a non-conductive epoxy. In this case, to dry theadhesive, the acoustic element 27 may be heated or dried naturally. Whenthe acoustic element 27 is heated, a characteristic of the vibrationmaterial layer 27-1 may be deteriorated. Accordingly, the acousticelement 27 may be dried naturally to attach the acoustic element 27 tothe inside of the vibration plate 29-1, even though time is required. Inaddition, in a case where sound quality required to the acoustic element27 is not high (for example, a case where a receiver providing anotherparty's voice in a telephone, or the like), the acoustic element 27 maybe dried by applying heat.

The vibration material layer 27-1 includes a piezoelectric material thatis vibrated by an electric field applied through the pair of electrodes27-2 positioned, and the piezoelectric material may be polyvinylidenefluoride (PVDF), lead zirconium titanate (PZT) ceramics, or the like.

The PVDF includes polyvinylidene fluoride trifluoroethylene (PVDF-TrFE),and may be easily manufactured in a flexible film form. The PZT mightnot be easily manufactured in a flexible film form as compared with thePVDF, and thus the PZT might not have a flexible characteristic.According to an exemplary embodiment of the present invention, the PZTmay be mixed with the PVDF (or PVDF-TrFE) and thus, the PZT may be usedas the vibration material layer 27-1 and formed in a flexible film form.

The pair of electrodes 27-2 is positioned at both sides of the vibrationmaterial layer 27-1, respectively, and provides an electric field to thevibration material layer 27-1. The electrodes 27-2 may use variousconductive materials such as a transparent conductor such as ITO andIZO, an opaque metal, a conducting polymer, carbon nanotubes (CNT), orthe like.

The acoustic element 27 is attached to the inside of the vibration plate29-1 of the rear chassis 28 and vibrates. In addition, the vibrationplate 29-1 vibrates according to the vibration of the acoustic element27. In this case, since the fixing member 29 and the vibration plate29-1 are formed of a material which can easily vibrate as compared withthe first and second protruding regions 28-1 and 28-2, the whole part ofthe rear chassis 28 might not vibrate. Accordingly, the vibration of thevibration plate 29-1 might not be transferred to the display panel 100.

Referring to FIG. 2, the first and second protruding regions 28-1 and28-2, the fixing member 29, and the acoustic element 27 have a circularstructure.

According to an exemplary embodiment of the present invention, a windowmade of tempered glass or plastic may be disposed on the front surfaceof the display panel 100. The window may prevent the front surface ofthe display panel 100 from being damaged from the outside. The windowmay form an outer surface of a display part of a portable electronicdevice such as a portable phone or other electronic devices.

Hereinafter, a display device in accordance with various modificationsof an exemplary embodiment of the present invention will be describedwith reference to FIGS. 3 to 5.

FIGS. 3 to 5 show the display device in accordance with variousmodifications of the exemplary embodiment of the present invention.

Although one acoustic element 27 is shown in FIG. 1, two or moreacoustic elements 27 may be provided, and a protruding region mayprotrude with various shapes (e.g., rectangular shape and ellipticalshape) instead of the circular shape.

FIGS. 3A to 3G illustrate the various shapes of the first and secondprotruding regions 28-1 and 28-2 and the vibration plate 29-1 in therear chassis 28. FIG. 2 illustrates the first and second protrudingregions 28-1 and 28-2 which cylindrically protrude.

The shapes of the rear surfaces of the first and second protrudingregions 28-1 and 28-2 are illustrated with various shapes such as anoval or a quadrangular structure having rounded edges in addition to thecircular shape. In addition, the shape may have a quadrangular structurehaving angular edges, a polygonal structure having round edges, or apolygonal structure having angular edges.

FIGS. 3A to 3G illustrate that the vibration plate 29-1 is located inthe second protruding region 28-2, and the shape of the vibration plate29-1 corresponds to the shapes of the first and second protrudingregions 28-1 and 28-2. However, the present invention is not limitedthereto. For example, the first and second protruding regions 28-1 and28-2 and the vibration plate 29-1 may have different shapes from eachother, in accordance with an exemplary embodiment of the presentinvention. Further, one or more acoustic elements 27 may be formed inthe vibration plate 29-1. In the case where one acoustic element 27 isformed, the acoustic element 27 may be disposed at the center of thevibration plate 29-1.

Referring to FIGS. 3A to 3B, one pair of the first and second protrudingregions 28-1 and 28-2 and the vibration plate 29-1 having substantiallythe same center may be formed on the rear chassis 28. Widths of ringsformed by the first and second protruding regions 28-1 and 28-2 and thevibration plate 29-1 may be substantially the same as each other (e.g.,FIG. 3B) or may be different from each other (e.g., FIGS. 3A and 3C).

Referring to FIGS. 3D to 3F, two pairs of the first and secondprotruding regions 28-1 and 28-2 and the vibration plate 29-1 may beformed on the rear chassis 28. In each pair, the first and secondprotruding regions 28-1 and 28-2 and the vibration plate 29-1 may havesubstantially the same center. In each pair, widths of the first andsecond protruding regions 28-1 and 28-2 and the vibration plate 29-1 maybe substantially the same as each other or may be different from eachother. In addition, sizes of the first and second protruding regions28-1 and 28-2 in one pair may be substantially the same as sizes of thefirst and second protruding regions 28-1 and 28-2 in the other pair(e.g., FIGS. 3D and 3E). In addition, sizes of the first and secondprotruding regions 28-1 and 28-2 in one pair may be different from sizesof the first and second protruding regions 28-1 and 28-2 in the otherpair (e.g., FIG. 3F).

Two pairs of the first and second protruding regions 28-1 and 28-2 andthe vibration plate 29-1 may be formed at a predetermined interval. Atleast one acoustic element 27 may be provided in each pair of the firstand second protruding regions 28-1 and 28-2 and the vibration plate29-1, and the acoustic element 27 may be located at the center of thevibration plate 29-1.

Referring to FIG. 3G, two pairs of first and second protruding regions28-1 and 28-2 and the vibration plates 29-1 may be overlapped with eachother. For example, two different pairs of first and second protrudingregions 28-1 and 28-2 and vibration plates 29-1 may be arranged to bepartially overlapped with each other to form one pair of first andsecond protruding regions 28-1 and 28-2 and one vibration plate 29-1.

In this case, at least one acoustic element 27 may be provided in thefirst and second protruding regions 28-1 and 28-2 and the vibrationplate 29-1. In the case where the two acoustic elements 27 arepositioned, the overlapped pair of first and second protruding regions28-1 and 28-2 is virtually divided into two circular protruding areas,and thus the two acoustic elements 27 may be positioned at the centersof the circular shapes, respectively, formed by the first and secondprotruding regions 28-1 and 28-2.

The shapes of the first and second protruding regions 28-1 and 28-2 andthe vibration plate 29-1 illustrated in FIGS. 3A to 3G shows some ofvarious modifications, but the present invention is not limited to theshapes illustrated in FIGS. 3A to 3G.

Hereinafter, a display device in accordance with an exemplary embodimentof the present invention will be described with reference to FIGS. 4 and5.

FIG. 4 illustrates a cross-section of the display device in which thetwo pairs of first and second protruding regions 28-1 and 28-2,vibration plates 29-1, and acoustic elements 27 are formed, for example,as shown in FIG. 3E.

Two light sources 21 may be provided, for example, at both ends of adisplay panel 100 as shown in FIG. 4 to supply light to the displaypanel 100 when the display panel 100 is relatively large. In this case,two pairs of the first and second protruding regions 28-1 and 28-2, thevibration plates 29-1, the acoustic elements 27 are formed to havesubstantially the same structure as each other.

According to the exemplary embodiment shown in FIG. 4, the two acousticelements 27 may produce different sounds to generate a stereo sound.Further, a sound in which low pitched frequencies are strengthened isproduced by the vibration plate 29-1. For example, the two acousticelements 27 may perform like a woofer when the low pitched frequenciesare strengthened. Thus, since the two acoustic elements 27 perform likethe woofer in addition to generation of the stereo sound, a 2.1 channelsound effect in this display device may be generated withoutadditionally using a woofer and speakers. In addition, the first andsecond protruding regions 28-1 and 28-2 may amplify the sound throughthe sound box therein. In FIG. 4, the display panel 100 is not shown,but the display panel 100 may be provided.

Referring to FIG. 5, an opening 28-3 is formed in the sound box providedby the first and second protruding regions 28-1 and 28-2 to dischargesound to the outside.

As shown in FIG. 5, the opening 28-3 is formed at a portion of the rearchassis 28. For example, the opening 28-3 may be formed at a portion ofthe first protruding region 28-1 or the second protruding region 28-2.In addition, the opening 28-3 may be formed along the circumference ofthe first or second protruding region 28-1 or 28-2.

Hereinafter, an acoustic element 27 in accordance with exemplaryembodiments of the present invention will be described with reference toFIGS. 6 to 8.

FIGS. 6 to 8 show various structures of the acoustic element 27 inaccordance with the exemplary embodiment of the present invention.

FIG. 6 illustrates a cross-section of a part of the acoustic element 27which includes a pair of electrodes 27-2 and a vibrating material layer27-1 disposed therebetween. The vibrating material layer 27-1 includes apiezoelectric material which vibrates according to an electric fieldapplied by the pair of electrodes 27-2 which are disposed in a verticaldirection, and examples of the piezoelectric material includepolyvinylidene fluoride (PVDF) and lead zirconate titanate (PZT)ceramic.

One electrode 27-2, hereinafter referred to as a lower electrode, isdisposed at an upper portion of the vibrating material layer 27-1, andthe other electrode 27-2, hereinafter referred to as an upper electrode,is disposed at a lower portion of the vibrating material layer 27-1. Inthe exemplary embodiment of FIG. 6, a part 27-21 of the lower electrode27-2 is extended to be above a part of the vibrating material layer27-1, surrounding a side of the vibrating material layer 27-1. The partwhich is disposed above the part of the vibrating material layer 27-1configures an electrode pad 27-21. Wires may be connected to the twoelectrodes 27-2 to apply an electric field to the vibrating materiallayer 27-1. In this case, as illustrated in FIG. 6, when the electrodepad 27-21 of the lower electrode 27-2 is extended to be disposed at anupper portion of the vibrating material layer 27-1, the two electrodes(e.g., the upper electrode 27-2 and the extended part 27-21 of the upperelectrode 27-2) may be directly connected at the upper portion of thevibrating material layer 27-1. Thus, even though the lower portion ofthe acoustic element 27 is attached by an adhesive, the electric fieldmay be applied through the two electrodes in the upper portion of thevibrating material layer 27-1.

FIG. 7 illustrates a top view of the acoustic element 27 having thecross-section of FIG. 6. Even though the two electrodes 27-2 (e.g., thelower and upper electrodes 27-2) are disposed above the acoustic element27, the upper electrode 27-2 may occupy a relatively large region of theacoustic element 27 and the electrode pad 27-21 extended from the lowerelectrode 27-2 may occupy a relatively small region. In addition, theelectrode pad 27-21 is spaced apart from the upper electrode 27-2 by apredetermined interval. In the exemplary embodiment of FIG. 7, theelectrode pad 27-21 has a quadrangular shape, and the upper electrode27-2 is disposed in a remaining portion of the circle except for wherethe electrode pad 27-21 is disposed. The vibrating material layer 27-1which is disposed below the electrode pad 27-21 and the upper electrode27-2 has a circular shape, and the lower electrode 27-2 also has acircular shape. The lower electrode 27-2 is extended to be connected tothe electrode pad 27-21 along a side of the vibrating material layer27-1. However, the present invention is not limited to the shapesdescribed with reference to FIG. 7.

Hereinafter, a multi-layered acoustic element 27 will be described withreference to FIG. 8.

Referring to FIG. 8, an acoustic element 27 in accordance with anexemplary embodiment of the present invention includes three vibratingmaterial layers 27-1 and four electrodes 27-2. The three vibratingmaterial layers 27-1 are arranged in a triple-layered structure, and thefour electrodes 27-2 are disposed on outermost sides of the vibratingmaterial layers 27-1 having the triple-layered structure and between thevibrating material layers 27-1. The four electrodes are electricallyconnected two by two and alternately disposed to each other. Forexample, a first electrode of the four electrodes 27-2 is disposed onthe bottom, a second electrode of the four electrodes 27-2 is disposedon the first electrode, interposing a part of the vibrating materiallayers 27-1 therebetween, a third electrode of the four electrodes 27-2is disposed on the second electrode, interposing a part of the vibratingmaterial layers 27-1 therebetween, and a fourth electrode of the fourelectrodes 27-2 is disposed on the third electrode, interposing a partof the vibrating material layers 27-1 therebetween. Different signals(e.g., voltage signals) are applied to the electrode 27-2 (e.g., thefirst electrode) disposed on the bottom and an electrode 27-2 (e.g., thefourth electrode) disposed on the top, and the fourth electrode 27-2 onthe top is extended along a side of the vibration material layers 27-1to be connected to the second electrode 27-2, and the first electrode27-2 on the bottom is extended along a side of the vibrating materiallayer 27-1 to be connected to be the third electrode 27-2. The firstelectrode 27-2 disposed on the bottom is further extended to be disposednext to the fourth electrode 27-2 on the top and to form an electrodepad 27-21 on the top, and thus the wiring lines may be easily connectedthereto. Thus, each vibrating material layer 27-1 are contacted with thetwo electrodes 27-2 which are positioned on the upper and lower portionsof each vibration material layer 27-1, respectively. When differentelectrical signals (e.g., voltages) are applied to the two electrodes27-2, an electric field between the two electrodes 27-2 may begenerated, the vibrating material layer 27-1 may vibrate, and thus asound corresponding to the vibration in the vibrating material layer27-1 may be generated. Acoustic pressure generated by the threevibrating material layers 27-1 of FIG. 8 may be higher than acousticpressure generated by one vibrating material layer of FIGS. 1 to 7.

Hereinafter, an amplifier 80 applying a signal to the acoustic element27 will be described with reference to FIG. 9.

FIG. 9 shows an amplifier 80 in a display device in accordance with anexemplary embodiment of the present invention.

Referring to FIG. 9, the amplifier 80 is disposed on a printed circuitboard (PCB) 78 in the display device. In addition, the amplifier 80 maybe disposed within a signal controller (not shown) which controls animage display of the display device, or may be formed separately fromthe signal controller. FIG. 9 illustrates an example in which theamplifier 80 is formed separately from the signal controller.

The output of the amplifier 80 is transferred to the display panel 100along the flexible circuit board 79 and is applied to the acousticelement 27 through an acoustic signal line 80-1 which is formed in thedisplay panel 100.

For example, the amplifier 80 receives and amplifies an acoustic signaltransferred from the outside, and transfers the acoustic signal to theacoustic element 27 through the acoustic signal line 80-1 in the displaypanel 100. The rear chassis 28 shown in FIG. 9 includes a wiringconnection member 28-4 to connect an acoustic signal wire 80-1 to theacoustic element 27, and the wiring connection member 28-4 protrudes andis connected to a first protruding region 28-1. For example, the wiringconnection member 28-4 may protrude in a narrowly raised circular wall.

The amplifier 80 may be implemented by various integrated circuits. Theamplifier 80 includes a single IC chip, and further includes a coil, acapacitor, and a resistor element disposed around the IC chip. Theacoustic signal applied to the amplifier 80 is provided from the outsideof the display device, and in the case of a portable terminal that auser carries, the acoustic signal may be provided from a control unitMPU of the portable terminal to the amplifier 80. FIGS. 10 to 14illustrate a display device sensing user's touch or motion thereto inaccordance with an exemplary embodiment of the present invention.

FIG. 10 illustrates sound pressure levels as a function of frequency,and hereinafter, a haptic function implemented by using vibration of theacoustic element 27 in a frequency band out of an audio frequency bandwill be described with FIG. 10.

Vibration is generated all over in the display device by the acousticelement 27, and vibration in a low frequency band out of the audiofrequency band may be generated as illustrated in FIG. 10 (see e.g., acircular line). A human, hereinafter referred to as a “user”, might nothear the low frequency band out of the audio frequency band. Thus, eventhough the vibration in the low frequency band is used for anotherpurpose other than generating a sound, sound quality might not beaffected. A change in vibration occurring when the user touches thedisplay device may be detected to detect the touch. The detection of thetouch may be a detection of whether the touch is present, and may beused together with a haptic function in an exemplary embodiment of thepresent invention. For example, the vibration in the low frequency bandother than the audio frequency band which is provided by the acousticelement 27 is used to detect the change in vibration to determinewhether there is a touch from the user, and thus the haptic function isimplemented. To this end, a sensor for detecting the vibration in thelow frequency out of the audio frequency may be further provided, and asignal controller which displays an image in the display device or acontrol unit (MPU) of a portable terminal may implement the hapticfunction using the sensor.

Hereinafter, a display device detecting pressure applied thereto will bedescribed with reference to FIG. 11.

A vibrating material layer 27-1 which is included in the acousticelement 27 generates a sound when the vibrating material layer 27-1vibrates by an electric field. In addition, the vibrating material layer27-1 vibrates even when the electric field is not applied thereto andthe vibration of the vibrating material layer 27-1 may generate. Forexample, when the voltage in the vibrating material layer 27-1 isgenerated without applying the electric field thereto, it is determinedthat a displacement in the vibrating material layer 27-1 is generated.Thus, the displacement in the vibrating material layer 27-1 may begenerated by the pressure thereof, and thus the vibrating material layer27-1 may perform as a pressure detecting sensor.

To detect the pressure of the vibrating material layer 27-1 by using theacoustic element 27, a sensor 85 for detecting a voltage which isgenerated in the acoustic element 27 may be further provided. Accordingan exemplary embodiment of the present invention, a structure of theamplifier 80 is changed to serve as a pressure sensor as well as anamplifier by driving as the amplifier and/or the sensor in a timedivisional manner.

FIG. 12 illustrates an exemplary embodiment in which motion of hands ofthe user is detected using a Doppler effect.

A sound wave in a high frequency band or a low frequency band out of theaudio frequency is generated in an acoustic element 27 which is disposedin a display device. For example, when a user moves hands in front ofthe display device, the sound wave is changed to be input to amicrophone 130 of a portable terminal. As illustrated in FIG. 13, thesound wave is transmitted to the microphone 130 while acoustic pressureof the sound wave becomes strong or weak by the Doppler effect due tothe user's motion (e.g., moving the user's hands). Thus, the change inacoustic pressure of the sound wave may be detected and the user'smotion (e.g., motion sensing) may be sensed.

To sense the user's motion by using the acoustic element 27, themicrophone 130 may be provided, as illustrated in FIG. 12. When adisplay device including the acoustic element 27 is used for anelectronic device including the microphone 130, the motion sensing maybe achieved without using an additional element.

Unlike a motion sensing using a camera, the motion sensing according tothe exemplary embodiment of the present invention, as illustrated inFIG. 12, may not require the image processing using the camera, maydetect the acoustic pressure of the sound wave which is input to themicrophone 130 to sense the user's motion, and may be relatively simplein structure.

Hereinafter, battery charging of a portable terminal using an acousticelement 27 will be described with reference to FIG. 14.

Referring back to FIG. 11, when the vibrating material layer 27-1 whichis included in the acoustic element 27 vibrates without an electricfield applied thereto, a voltage is generated from the vibratingmaterial layer 27-1. In addition, the voltage generated as describedabove is stored in a capacitor or a battery 87 to increase a usage timeof the battery. For example, since a portable terminal is carried by theuser, the portable terminal may have a predetermined level of vibration.Thus, when the acoustic element 27 is included to the portable terminal,the acoustic element 27 vibrates without the electric field appliedthereto to generate a voltage. The generated voltage by the acousticelement 27 may be transmitted to the battery 87 to charge the battery87.

Further, if the portable terminal is not charged, the user may shake theportable terminal which includes the acoustic element 27 or touch theportable terminal by using the user's fingers to charge the battery 87.For example, the number of shaking and touching times the portableterminal may be from several tens to several hundreds.

As described above, when a display device includes a single acousticelement 27, operations (e.g., detecting user's touch or motion, orcharging a battery of a portable terminal by using vibration in avibration material layer 29) of the display device described withreference to FIGS. 10 to 14 may be achieved by driving the acousticelement 27 in the display device in a time divisional manner. Further, aseparate acoustic element 27 may further be formed in the displaydevice. In this case, the separate acoustic element 27 might not beconnected to the amplifier and may be connected to a sensor or a batteryto perform detecting the user's touch or motion or charging the battery.

Even though the acoustic element 27 is described as being disposed inthe display device, the acoustic element 27 might not be disposed in thedisplay device. For example, the acoustic element 27 may be disposed insome part of the portable terminal in which the display device is usedto provide the operations illustrated in FIGS. 10 to 14 and might not benecessarily disposed in the display device.

Although the present invention has been described with reference toexemplary embodiments thereof, it will be understood that the presentinvention is not limited to the disclosed embodiments and modificationsand equivalent arrangements are included within the spirit and scope ofthe appended claims.

What is claimed is:
 1. A portable terminal, comprising: a displaydevice; and a peripheral region adjacent to the display device, theperipheral region including a microphone, wherein the display deviceincludes: a display panel configured to display an image: and a firstacoustic element disposed behind the display panel, the first acousticelement for generating a sound wave, wherein the microphone isconfigured to receive the sound wave generated by the first acousticelement, while the first acoustic element generates the sound wave,wherein the display device is configured to detect a change in the soundwave received by the microphone disposed within the peripheral regioncompared to the sound wave generated in the acoustic element disposedbehind the display panel to sense an object out of the display device,and wherein a path of the sound wave used to sense the object initiatesbehind the display panel, is reflected off of the object out of thedisplay device, and is received at the peripheral region of the portableterminal.
 2. The portable terminal of claim 1, wherein the firstacoustic element is configured to generate the sound wave having a firstfrequency other than an audible frequency.
 3. The portable terminal ofclaim 2, wherein the change in the sound wave includes a change in thefirst frequency.
 4. The portable terminal of claim 1, wherein thedisplay device is configured to sense an existence or a motion of theobject by using an acoustic pressure of the sound wave received by themicrophone.
 5. The portable terminal of claim 1, wherein the firstacoustic element overlaps a central area of the display panel.
 6. Theportable terminal of claim 1, further comprising: a rear chassisdisposed behind the display panel, wherein the first acoustic element isdisposed between the display panel and the rear chassis.
 7. The portableterminal of claim 6, wherein the rear chassis has at least one openingconfigured to discharge the sound wave.
 8. The portable terminal ofclaim 1, further comprising: a first vibration plate disposed behind thedisplay panel, wherein the first acoustic element overlaps a centralarea of the first vibration plate.
 9. The portable terminal of claim 8,wherein a planar area of the first acoustic element is enclosed by anouter boundary of the first vibration plate in a plan view.
 10. Theportable terminal of claim 8, wherein the first vibration plate includesa leather, an artificial leather, or a polyetherimide (PEI) film. 11.The portable terminal of claim 1, wherein the first acoustic elementincludes a first electrode, a second electrode facing the firstelectrode, and a vibration material layer provided between the first andsecond electrodes, and the vibration material layer is separated fromthe first vibration plate by the first electrode or the secondelectrode.
 12. The portable terminal of claim 8, further comprising: asecond acoustic element disposed behind the display panel and spacedapart from the first acoustic element.
 13. The portable terminal ofclaim 12, further comprising: a second vibration plate disposed behindthe display panel, wherein the second acoustic element overlaps acentral area of the second vibration plate.
 14. The portable terminal ofclaim 1, further comprising: an amplifier configured to amplify anacoustic signal; and an acoustic signal wire configured to transfer theacoustic signal from the amplifier to the first acoustic element. 15.The portable terminal of claim 14, further comprising: a printed circuitboard and a flexible printed circuit board, wherein a substrate of thedisplay panel is connected with the printed circuit hoard through theflexible printed circuit board, and wherein the amplifier is disposed onthe printed circuit board.
 16. The portable terminal of claim 1, furthercomprising: a battery configured to supply power to the display device,wherein the battery is charged by a voltage generated when the firstacoustic element vibrates.